Catheter systems such as angioplasty catheters, and stent delivery systems, as well as the stents associated therewith, are widely used in the treatment of stenoses, aneurysms, lesions, and other abnormalities within blood vessels and other body lumens. Intravascular stents are used in coronary, renal, and carotid arteries, for example, to maintain an open passage through the artery. In patients whose coronary heart disease consists of focal lesions, stents have proven effective. For example, where only a single coronary artery is clogged or where there are short blockages in more than a single artery, stents have been used with a great amount of success. An intravascular stent may be positioned in a clogged artery by a catheter and is often set in place by inflating a balloon upon which the stent is mounted. This expands the diameter of the stent and opens the previously clogged artery. The balloon is then deflated and removed from the patient while the stent retains an open passage through the artery.
Treatment at bifurcation sites has been difficult. Although efforts have been made to use a stent at bifurcations, these sites have previously been problematic to treat. The specialty stents designed for bifurcations generally need specific alignment, radially as well as longitudinally. For example, U.S. Pat. No. 5,749,825 is representative of a catheter system that is intended to treat stenoses at an arterial bifurcation. The disclosure of U.S. Pat. No. 5,749,825 is hereby incorporated by reference.
Often stent delivery systems are employed to deliver multiple stents to the primary and/or secondary vessels surrounding a vessel bifurcation. One or more catheters may be required to deploy each stent. Stents deployed by such systems generally have an opening or branch which allows for unimpeded blood flow into a side branch artery, and through which one or more branch stents may be subsequently delivered. However, problems are still encountered in orienting such stents relative to the branch openings at the bifurcation of the primary and secondary passages. Moreover, such bifurcated assemblies are typically specially manufactured at an increased cost over a more standard stent intended for single vessel deployment.
In delivering one or more stents to a vessel bifurcation, many devices have relied on the application of torque to the catheter shaft from outside of the patient to orient one or more medical devices within the vessel passage. The use of such active application of torque on a catheter within a vessel has several possible consequences including potential strain inadvertently applied to the contacted vessel, as well as control and precision issues. To avoid the need of having to actively apply torque to the catheter shaft, in order to orient the and/or stent, catheter assemblies have been developed which are equipped with a rotatable sheath, that is capable of rotating about the catheter shaft and/or balloon. A stent may be initially mounted to the sheath and a secondary guidewire engaged to the sheath directs the orientation of the sheath as the assembly is advanced through a body lumen. Some examples of such catheter assemblies have been shown and described in the following publications:
U.S. patent application Ser. No. 10/375,689, filed Feb. 27, 2003 and U.S. patent application Ser. No. 10/657,472, filed Sep. 8, 2003 both of which are entitled Rotating Balloon Expandable Sheath Bifurcation Delivery; U.S. patent application Ser. No. 10/747,546, filed Dec. 29, 2003 and entitled Rotating Balloon Expandable Sheath Bifurcation Delivery System; U.S. patent application Ser. No. 10/757,646, filed Jan. 13, 2004 and entitled Bifurcated Stent Delivery System; and U.S. patent application Ser. No. 10/784,337, filed Feb. 23, 2004 and entitled Apparatus and Method for Crimping a Stent Assembly; the entire content of each of which are incorporated herein by reference.
Upon a review of the above referenced publications it will be recognized that contact between the sheath and the balloon, and/or the catheter shaft, will affect the capability of the sheath to readily and freely rotate. Desirably the frictional interface between the sheath and balloon, and/or catheter shaft, should be minimized to encourage the free rotation of the sheath. In addition, it would be further desirable to provide such rotatable sheaths with one or more configurations that may provide a more directed or controlled delivery of the stent during balloon expansion.
All U.S. patents and applications and all other published documents mentioned anywhere in this application are incorporated herein by reference in their entirety.
Without limiting the scope of the invention a brief summary of some of the claimed embodiments of the invention is set forth below. Additional details of the summarized embodiments of the invention and/or additional embodiments of the invention may be found in the Detailed Description of the Invention below.
A brief abstract of the technical disclosure in the specification is provided as well only for the purposes of complying with 37 C.F.R. 1.72. The abstract is not intended to be used for interpreting the scope of the claims.